Carbon black process

ABSTRACT

A carbon black reactor is comprised of a housing which defines a precombustion zone, a reaction zone and a quench zone which are in flow communication. Inlet means open into the precombustion zone or the reaction zone and is operable to introduce make hydrocarbon into the reactor. Also, inlet means open into the precombustion zone and is operable for the introduction of hot combustion gases into the precombustion zone. The make hydrocarbon is pyrolyzed by contact with the hot combustion gases as same flow along the reaction zone. After a predetermined time as determined by the length of flow along the reaction zone, the effluent produced by the pyrolysis of the make hydrocarbon by contact with the combustion gases is quenched to stop the reaction. A tubular member extends into the quench zone and has oppositely directed discharge openings on opposite sides thereof wherein a fluid coolant is introduced into the quench zone through the openings to form a curtain of coolant across the width of the quench zone through which the effluent must pass wherein same is cooled by contact with the coolant.

This is a division of application Ser. No. 764,665, filed Feb. 1, 1977,now U.S. Pat. No. 4,138,217.

Many devices have been used to effect quenching of the reaction in acarbon black reactor to stop the pyrolysis of the make hydrocarbon.However, some of the difficulties in the past have exemplifiedthemselves in nonuniform quenching and incomplete quenching which thenresults in lower quality carbon black because of the variation inparticle size distribution and in the photelometer thereof. Nozzles ofmany kinds and positions are known in the art and are somewhat effectiveto accomplish the quenching. However, one of the problems is that tohave a nozzle effective to provide a spray of coolant such as water intothe quench zone a large nozzle and feed pipe have been required whichthen in turn provides resistance to flow for the effluent. Typical ofthis type of fluid injector is the nozzle disclosed in U.S. Pat. No.2,897,062, issued July 28, 1959 wherein radially directed dischargeopenings introduce water into the quench zone. Also, inwardly radiallydirected water quench ports are known as discussed in U.S. Pat. No.3,011,872, issued Dec. 5, 1961, but such do not provide a uniformdistribution of coolant across the quench zone. The present inventionprovides an improved coolant injector which is effective to form auniform distribution of coolant across the quench zone, and ofrelatively narrow length along the direction of the effluent or smokeflow, to provide rapid and uniform cooling of the effluent flowing alongthe quench zone. The injection means of the present invention providesminimal resistance to flow. Also, the injection means is of simpleconstruction and inexpensive to manufacture from readily availablematerials without costly machining.

The principal objects and advantages of the present invention are: toprovide a carbon black reactor with an improved coolant or quenchinjection means which will result in a more uniform distribution ofcoolant across the quench zone which will result in a more uniformquenching of the effluent especially needed at the prequench position;to provide such an apparatus which is simple in construction and easy tomaintain and manufacture; and to provide such an apparatus which is welladapted for its intended use.

Other objects and advantages of the present invention will becomeapparent from the following detailed description taken in connectionwith the accompanying drawings wherein are set forth by way ofillustration and example certain embodiments of this invention.

FIG. 1 is a somewhat schematic illustration of a carbon black reactorembodying the present invention.

FIG. 2 is an enlarged sectional view showing structural details of theinjection means.

FIG. 3 is a sectional view of the injection means taken along the line3--3, FIG. 2.

FIG. 4 is a schematic view of a modified form of the invention.

FIG. 5 is a schematic view of a modified form of the invention.

FIG. 6 is a sectional view, similar to FIG. 3, of a modified form of theinjection means.

Referring more in detail to the drawings

The reference numeral 1 designates generally a carbon black producingapparatus or reactor which can be of any suitable type such as thoseknown in the art as is disclosed in U.S. Pat. No. 2,564,700. A housing 2forms the reactor and has positioned therein a precombustion zone 3which has in communication therewith a reaction zone 4 which isflow-wise downstream of the precombustion zone and downstream of thereaction zone 4 is a quench zone 5. There is no sharp line ofdemarcation between the particular zones and same are determined by theparticular process taking place therein. In communication with theprecombustion zone 3 there is provided a make-hydrocarbon, sometimescalled oil, injector 6 which is operable for the injection of amake-hydrocarbon into either the precombustion zone 3 or the reactionzone 4. Also, there is provided in the precombustion zone 3 inlet means7 which is operable for introducing hot combustion gases which can be acombustible fuel and air or oxygen or a burning mixture of same into theprecombustion zone 3 wherein same by contact with the make-hydrocarbonpyrolyzes the make-hydrocarbon to form a carbon black particlecontaining effluent, usually referred to as smoke. The pyrolysis takesplace in the reaction zone and after a predetermined time, a certaintype of black, i.e., as determined by the particle size, structure,photelometer, etc., is formed. Depending upon the particular carbonblack desired to be formed, the pyrolysis reaction is stopped byquenching or prequenching the smoke effluent which is preferablyaccomplished by direct contact with a coolant such as water or steam.This can also be accomplished by contact with a cool gas such asnitrogen or recycled smoke. However, one of the preferred coolants iswater.

Although a vortex or swirl type reactor is illustrated it is to beunderstood that any suitable type of reactor can be used with thepresent invention.

The quench zone has extending thereinto an injector or inlet means 9which, as shown, is comprised of a hollow tubular member 10 whichextends into the quench zone, i.e., generally from one side to anopposing side, and preferably same extends through the center or thelongitudinal axis of the quench zone. However, this position can bevaried if two or more of the injectors are used. Many arrangements canbe made if a plurality of tubular members are used. Also, a free end 11can have a discharge orifice 12 to direct spray of coolant from the end.In the form shown in FIG. 1, one tubular member is positioned generallyperpendicular or normal to the longitudinal axis of the quench zone andhas the free end 11 thereof positioned adjacent to a side of the quenchzone opposite the side which the tubular member extends through thehousing 2. When one tubular member is used it is preferred that sameextend substantially across the width of the quench zone, i.e., morethan half way. The tubular member 10 has a plurality of dischargeopenings 12 positioned generally on opposite sides thereof and aredirected to spray a coolant in a plane generally transverse to thelongitudinal axis of the quench zone. However, the tubular member 10 canbe canted in an upstream or downstream direction and still achieveacceptable results. Also, the discharge openings 12 can be directedsomewhat upstream or downstream, say for example up to about 30° andstill achieve adequate cooling. Therefore, the term "generallytransverse" is to be broadly interpreted. The feature of the tubularmember as the coolant injector is that by having the discharge openingdirected generally transverse is that a curtain of coolant is providedacross substantially the entirety of the cross section of the quenchzone. This can be accomplished with one or more tubular members, as forexample: two tubular members extending into the quench zone fromopposite sides and being generally diametrically opposed (FIG. 4), aplurality of tubes circumferentially spaced apart and extending radiallyinto the quench zone (FIG. 5), etc.

In a preferred form of the invention, the tube has certain of thedischarge openings 12 on one side and the remaining discharge openingson the other side, i.e., 180° apart on a round tube, and are directedaway from the tube and are generally normal to the longitudinal axis ofthe tubular member 10. It is preferred to help form a wide spray, in aplane transversely across the quench zone and with a narrow spray angleA to form a relatively thin curtain, that grooves 14 be recessedinwardly from the outer surface of the tube as, for example,approximately 1/16" (0.159 cm) deep with the discharge openings 12 onthe respective side opening into the respective groove 14. These groovesmay be "V" shaped with the hole at the bottom or apex of the "V" as seenin FIG. 6 or generally rectangularly shaped as seen in FIG. 3. The angleB preferably is between about 15° and 60° and preferably between about30° and 45°. It has been found by actual operation in a 15-inch diameterreactor zone that a tubular member 10 having an outside diameter ofapproximately 3/4 inch (1.91 cm) is adequate to supply sufficient waterto effect the quenching.

It is preferred to achieve uniform distribution of coolant from theinjector 9 that discharge openings in various positions or of varioussizes can be used. One way to achieve a uniform distribution is byhaving the discharge openings in varying spaced distances along thelength of the tubular member 10 wherein the space between the dischargeopenings decreases the further from an inlet end 15 of the tubularmember whereby pressure drop in the coolant along the length of thetube, i.e., the closed end 16 of the tube having the lowest pressure hasthe discharge openings more closely spaced together then the dischargeopenings 12 adjacent the inlet end 15 to provide for a uniform flow rateinto the quench zone along the length of the tubular member 10. Thisprovides for a more uniform amount of water to be introducedtransversely across the area of the quench zone, whether it be adjacentthe inlet end 15 or the closed end 16.

Another way to achieve uniform distribution of coolant across the widthof the quench zone is to have the discharge openings sized differentlywherein the further from the inlet end the larger diameter the dischargeopening so as to allow a uniform flow rate of coolant into therespective areas of the quench zone. The further from the inlet end, thelarger the discharge opening, i.e., the discharge opening size increasesaway from the inlet end. The exact size or positions of the dischargeopenings 12 can be determined by calculation or trial and error toachieve optimum distribution of coolant.

A third way to assure more uniformity of coolant into the quench zone isby determination of the area into which the particular discharge openingmust inject coolant to effect the cooling whereby at a position adjacentthe center of the quench zone the discharge opening most adjacentthereto having more cross-sectional area across the width of the quenchzone by virtue of being further from the side of the quench zone atwhich same is directed wherein the discharge opening adjacent the centeris slightly larger than those positioned on opposite sides thereof.Therefore, this compensates for both pressure drop and area across whichthe coolant must be distributed from the particular discharge opening.

Prequench lowers the smoke temperature to below carbon black formingconditions, e.g., to below about 2100° F. (1150° C.). Final watercooling is to about 1200° F. (649° C.). Smoke is further cooled byindirect exchange to about 450° F. (232° C.).

By way of operation, the following calculated example is provided toshow operability of the present invention.

    ______________________________________                                        Reactor Unit:                                                                 Precombustion Zone                                                            Diameter, inches,  39      (99.06 cm)                                         Length, inches,    12      (30.48 cm)                                         Reaction Tube: (measured                                                      from downstream                                                               end of the precombustion zone)                                                Length, inches     112                                                        Diameter, inches,  15      (38.10 cm)                                         Length to Prequench, inches,                                                                     48*     (121.92 cm)                                        Length to Final Quench, inches,                                                                  112     (284.48 cm)                                        Operation:                                                                    Make Oil, 120 BMCI, 700° F.                                            (371.1° C.) Mid-Boiling Point                                          (Aromatic Oil), gallons/hr,                                                                      325     (1230.13 liters/hr)                                Tangential Air, SCF/hr,                                                                          210,000 (5950.69 m.sup.3 /hr)                              Tangential Fuel Gas, (Methane)                                                SCF/hr,            13,680  (387.65 m.sup.3 /hr)                               Axial Air, SCF/hr, 4,000   (113.35 m.sup.3 /hr)                               Prequench Water                                                               at 100° F. (37.8° C.)                                           g/h, (to about 2000° F.)                                                                  175     (586.68 liters/hr)                                 Final Quench Water                                                            at 100° F. (37.8° C.)                                           g/h, (to about 1200° F.)                                                                  450     (1703.25 liters/hr)                                Carbon Black Properties                                                       (pelleted and dried):                                                         Based on prequenching at                                                      the 48"  prequench locus                                                      N.sub.2 SA, m.sup.2 /gm, (1)                                                                     99                                                         CTAB, m.sup.2 /gm, (2)                                                                           100                                                        24M4, DBP, cc/100 gm, (3)                                                                        101                                                        Photelometer, (4)  86                                                         The Prequench Tube:                                                           External Diameter, inches,                                                                       11/16   (1.746 cm)                                         Internal Diameter, inches,                                                                       7/16    (1.111 cm)                                         Size of Orifices, diameter, inches,                                                              1/16    (0.159 cm)                                         Size of Groove:                                                               Width, inches,     1/16    (0.159 cm)                                         Depth, inches,     1/16    (0.159 cm)                                         Spacing of Orifices:                                                          First Set (180° apart), inches                                         from inside of reactor wall                                                   adjacent the inlet end of                                                     tube               41/2    (11.43 cm)                                         Second Set from First, inches                                                                    13/4    (3.94 cm)                                          Third Set from Second, inches                                                                    11/2    (3.81 cm)                                          Fourth Set from Third, inches,                                                                   11/4    (3.18 cm)                                          Fifth Set from Fourth, inches                                                                    1       (2.54 cm)                                          Sixth set from Fifth, inches                                                                     1/2     (1.27 cm)                                          Distance of                                                                   Closed End from Reactor                                                       Inner Wall, inches,                                                                              41/2    (11.43 cm)                                         ______________________________________                                         *(Prequench pipes are at 36" (91.44 cm), 42" (106.68 cm), 48" (121.92 cm)     and one is selected for that type carbon black to be                          (1) ASTM D3037-71T, Method A;                                                 (2) Janzen, J. and Kraus, G., Rubber Chemistry and Technology, 44, 1287       (1971);                                                                       (3) U.S. Pat. No. 3,548,454 as measured after crushing by Method B,           ASTMD2414-70;-                                                                (4) ASTM D1618-58T.                                                      

By use of the present invention, more efficient, uniform, rapid coolingof the effluent should be realized wherein less water could be used toattain the desired prequenching result over various injection meanscurrently used, or for the same amount of quench liquid introduced it isbelieved that a more uniform particle distribution which would result inhigher tinting strength (ASTM D-3265-75) can be realized.

It is to be understood that while there has been illustrated anddescribed certain forms of this invention it is not to be limited to thespecific form or arrangement of parts herein described and shown exceptto the extent that such limitations are found in the claims.

That which is claimed is:
 1. A method of producing carbon blackcomprising the steps of:producing hot combustion gases; contacting amake hydrocarbon with said thus produced hot combustion gases in arection zone and thereby pyrolyzing said make hydrocarbon so as toproduce an effluent comprising carbon black; flowing said thus producedeffluent along a quench zone having a longitudinal axis; introducingquench liquid into said quench zone from a plurality of oppositelydirected discharge openings lying in a plane generally transverse to thelongitudinal axis of the quench zone and being spaced apart at differentdistances outwardly from the longitudinal axis of such quench zone andextending substantially across the cross section of said quench zone soas to form a curtain of quench liquid extending substantially across theentirety of the cross-section of the quench zone.